Cable connector

ABSTRACT

A method and means for connecting a multi-conductor electrical cable to an electrode assembly having inner and outer electrically conductive connectors, comprising a socket cap molded from an electrically conductive material, the socket cap including a bore, the electrode assembly adapted to extend into the bore with the outer connector thereof electrically contacting the wall of the cap in the bore. The cable is imbedded within the socket cap with a first of the conductors thereof in electrical contact therewith whereby the first conductor electrically contacts the outer connector via the socket cap. A connector pin is electrically connected to a second of the conductors of the cable, the connector pin being positioned within and aligned with the axis of the bore in the cap whereby the connector pin contacts the inner connector of the electrode assembly. A piece of shrink tubing is utilized to cover and insulate the second conductor and the connector pin from the cap and the first conductor.

United States Patent J errold-J ones [54] CABLE CONNECTOR [72] Inventor: Paul Jerrold-Jones,

Calif.

[73] Assignee: Beckman Instruments, Inc.

[22] Filed: June 24, 1970 [21] Appl. No.: 49,457

Claremont,

[52] US. Cl. ..339/ 177 R, 29/629, 174/75 C, 174/DIG. 8, 264/104, 264/272, 339/218 R,

[51] Int. Cl. ..H0lr 17/06 [58] Field of Search ..339/177, 218, 275 R, 275 T, 339/278 C; 29/628, 629; 174/75 C, 88 C,

DIG. 8; 264/104, 105, 230, 249, 272

Primary Examiner-Marvin A. Champion Assistant Examiner-Lawrence J. Staab Attorney--Thomas L. Peterson and Robert J. Steinmeyer [57] ABSTRACT A method and means for connecting a multi-conductor electrical cable to an electrode assembly having inner and outer electrically conductive connectors, comprising a socket cap molded from an electrically conductive material, the socket cap including a bore, the electrode assembly adapted to extend into the bore with the outer connector thereof electrically contacting the wall of the cap in the bore. The cable is imbedded within the socket cap with a first of the conductors thereof in electrical contact therewith whereby the first conductor electrically contacts the outer connector via the socket cap. A connector pin is electrically connected to a second of the conductors of the cable, the connector pin being positioned within and aligned with the axis of the bore in the cap whereby the connector pin contacts the inner connector of the electrode assembly. A piece of shrink tubing is utilized to cover and insulate the second conductor and the connector pin from the cap and the first conductor.

9 Claim, 3 Drawing Figures PATENTEI'Jwc 15 I972 INVENTOR. A414 JERROLO-JO/VES BY Z 1 4 W ATTORNEY CABLE CONNECTOR BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-conductor electrical cable connector and, more particularly, to a connector assembly for connecting the center conductor and outer shield of a coaxial cable to the inner and outer electrically conductive connectors, respectively, of an electrode assembly.

2. Description of the Prior Art A wide variety of electrochemical electrode assemblies exist which require removable socket caps for making electrical connection between the connectors of the assemblies and multiconductor electrical cables such as coaxial cables. Such electrode assemblies include, for example, pH electrodes, oxygen sensors and specific-ion electrodes. Electrode assemblies of these types typically include an inner, male, electrically conductive connector which is connected via a conductor to the sensing portion of the electrode assembly and an outer, male, electrically conductive connector which is connected to an electrostatic shielding member included within the electrode assembly housing. Available socket caps, therefore, typically include an inner female connector which is electrically connected to one of the conductors of the cable such as the center conductor of a coaxial cable, the inner connector of the cap adapted to contact the inner connector of the electrode assembly, and an outer female connector which is electrically connected to another of the conductors of the cable such as the shielding of a coaxial cable, the outer connector of the cap adapted to contact the outer connector of the electrode assembly.

Several problems exist with presently available, removable, socket caps. In the first instance, the conventional method for connecting the inner female connector of the cap to the center conductor of the coaxial cable, which must be designed to prevent the inner connector from slipping within the connector assembly, is to swage the inner connector which tends to open up the hole therein which receives the center conductor and makes soldering more difficult, especially if the center conductor is of very small diameter. Secondly, in order to make electrical connection between the outer connector of the electrode assembly and the shield of the coaxial cable, it is common to use a metal sleeve. This is not only expensive, but makes it necessary to use solder or some other mechanical means for making electrical connection between the metal sleeve and the cable shield. The resulting configuration requires slow, cumbersome assembly methods which further increase the total cost of the cable connector.

SUMMARY OF THE INVENTION According to the present invention, there is provided a novel cable connector which not only eliminates the problems present in the prior art but also adds several unique features. The present method and means of construction eliminates the need for expensive metal parts and slow, cumbersome assembly methods. The present cable connector has a substantially simpler construction than prior cable connectors and can be made in substantially smaller sizes. The present cable connector can be made at low cost and with the cable at any angle to the axis of the connector. The present cable connector utilizes a conductive molding compound instead of the conventional metal sleeves to make electrical connection to the outer connector of the electrode assembly. By using a conductive molding compound, the need for solder or some other mechanical means for making electrical connection to the cable shield is eliminated. In addition to providing electrical connection to the cable shield, the conductive molding compound can be molded into any convenient shape to provide a finished configuration which functions as a handle, all in a single operation.

Briefly, the present method and means for connecting a multi-conductor electrical cable such as a coaxial cable to an electrode assembly having inner and outer electrically conductive connectors first requires the coaxial cable to be stripped to expose its shield, its center conductor and the insulation between the shield and the center conductor. Thereafter, a connector pin may be inserted into a pin holder and a washer is slipped over the exposed end of the pin. The center conductor of the coaxial cable is inserted into the pin and the entire assembly is soldered thereby connecting the washer, the center conductor and the pin. The washer, soldered to the connector pin, is used as a lock to prevent the pin from slipping out of the pin holder and breaking the electrical connection to the coaxial cable in the event that the connector pin sticks too tightly to the inner connector of the electrode assembly when disconnecting the cable. A piece of shrink tubing is slipped over the pin, washer and exposed center conductor, but not the exposed shield, and the tubing is shrunk down to insulate the pin, center conductor, washer and solder joint from the exposed shield as well as strengthening the joint so that the soldered electrical connection cannot be damaged in handling of the assembly. The subassembly is then put into a mold and a conductive molding compound is used to form the outer cap, the coaxial cable being imbedded within the cap whereby a permanent connection is made between the exposed shield of the cable and the conductive molding material. The cap is molded to include a bore which is coaxial with the connector pin. Therefore, as the completed cable connector is slipped over the end of the electrode assembly, electrical contact is completed between the center conductor of the cable and the inner connector of the electrode assembly via the connector pin and between the shield of the cable and the outer connector of the electrode assembly via the electrically conductive cap.

It is therefore an object of the present invention to provide a novel multi-conductor electrical cable connector.

It is a further object of the present invention to provide a method and means for removably connecting a multi-conductor electrical cable to an electrochemical electrode assembly.

It is a still further object of the present invention to provide a method and means for connecting the center conductor and shield of a coaxial cable to the inner and outer electrically conductive connectors, respectively, of an electrode assembly.

It is another object of the present invention to provide such a cable connector which eliminates the need for expensive metal parts and slow, cumbersome assembly methods.

It is still another object of the present invention to provide a cable connector which can be made in a relatively small size with the cable at any angle to the axis of the connector.

Another object of the present invention is the provision of a cable connector which utilizes a conductive molding compound in constructing the socket cap thereby eliminating the need for a mechanical means for making electrical connection to the shield of a coaxial cable.

Still another object of the present invention is the provision of a cable connector including a washer to prevent breakage of the electrical connection between the cable and a connector pin within the assembly.

An additional object of the present invention is the provision of a cable connector which utilizes a piece of shrink tubing to insulate various electrical connections.

Still other objects, features and attendant advantages of the present invention will become apparent to those skilled in the art from a reading of the following detailed description of the preferred embodiment constructed in accordance therewith, taken in conjunction with the accompanying drawings wherein like numerals designate like parts in the several figures and wherein:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view of the present cable connector in a first stage of construction;

FIG. 2 is a longitudinal sectional view of the present cable connector in a second stage of construction; and

FIG. 3 is a longitudinal sectional view of the present cable connector when completed, with the electrode assembly for use therewith also being shown in crosssection but detached from the cable connector.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, the present invention relates to a cable connector, generally designated 10, for connecting a multi-conductor electrical cable 11 to an electrode assembly, generally designated 12. Electrode assembly 12 may be, for example, a pH electrode, an oxygen sensor or a specific-ion electrode. For an example of one type of electrode assembly which may be used with the present invention, reference should be made to U.S. Pat. No. 3,476,672. Electrode assemblies of these types typically include an internal half cell (not shown) positioned within a tube 13 of non-conductive material. A cap assembly 14, as disclosed, for example, in said U.S. Pat. No. 3,476,672 may be included for providing a hermetic seal so that no leakage will occur between the parts of electrode assembly 12. An electrical lead 15 is connected between the internal half cell and an inner, male, electrically conductive connector 16. A foil shield 17 is usually positioned within body 13 to electrostatically shield the sensing portion of electrode assembly 12. Shield 17 is electrically connected to an outer, male, electrically conductive connector 18 which is coaxial with inner connector 16 and insulated therefrom by means of a non-conductive body 19.

Connector 10 is required for making a removable electrical connection between connectors 16 and 18 and cable 11. In this example, cable 11 would have two conductors corresponding to connectors 16 and 18. It will be understood, however, that the present invention is equally suited for use in any application wherein electrical connection is desired to any number of conductors. For example, connector 16 might be a female connector or there could be more than one, spaced, inner connectors similar to connector 16.

Also for purposes of example, connector 11 will be described as being a coaxial cable having a center conductor 20 (see FIG. 1) which is surrounded by a braided electrical shield 21. Conductors 20 and 21 are insulated from each other by an electrically non-conductive tubular element 22, cable 11 also including an outer insulator 23. According to the present invention, cable connector 10 is operative to connect inner conductor 20 and shield 21 of cable 11 to inner connector 16 and outer connector 18, respectively, of electrode assembly 12.

Referring now primarily to FIG. 1, the present method and means for connecting cable 11 to electrode assembly 12 first requires that cable 11 be stripped to expose, in the following sequence, center conductor 20, insulation 22, and shield 21. A female, tubular connector pin 24 is provided having an inner diameter of essentially the same dimension as the outer diameter of connector 16. Connector pin 24 may include a plurality of slots 25 to provide flexibility in the connector for friction fit with male connector 16. According to a preferred embodiment of the present invention, connector pin 24 is inserted into a pin holder 26 which is made from an electrically non-conductive material such as plastic. Pin holder 26 is an elongated member having first and second coaxial bores 27 and 28 therein. The diameter of bore 27 is essentially the same as the outer diameter of connector pin 24, thereby providing a friction fit between connector pin 24 and pin holder 26. The diameter of bore 28 is greater than the diameter of bore 27 to provide for a slight flare at the open end of connector pin 24 for ease in seating connector 16 in connector pin 24. Alternatively, a single bore may be provided through pin holder 26 which would exactly correspond to the outer dimensions of connector pin 24. In addition, pin holder 26 includes an annular flange 29 adjacent the open end of connector pin 24 for reasons which will appear more fully hereinafter.

After cable 11 is stripped as described previously, connector pin 24 is inserted into pin holder 26. A metal washer 30 is slipped over the closed end of pin 24. The inner diameter of washer 30 is such that washer 30 will only partially extend over pin 24, as shown. A piece of heat shrinkable tubing 31, to be described more fully hereinafter, is slipped over the stripped end of cable 11 and, at the present time, positioned away from the stripped end of cable 11, as shown in FIG. 1. Tubing 31 is formed with an elongated slot 33 adjacent to its upper end, through which cable 11 extends. Center conductor 20 is then inserted into a small hole at the apex of connector pin 24 and bent at any desired angle.

The subassembly consisting of cable 11, connector pin 24, pin holder 26 and washer 30 is then inverted and dip soldered. During the dip solder operation, the solder 32 simultaneously, electrically connects washer 30 and center conductor 20 to connector pin 24.

Referring now to FIG. 2, shrink tubing 31 is generally cylindrical and open at both ends thereof. According to the preferred embodiment of the present invention, shrink tubing 31 is a double layer structure, an inner layer 40 being formed of polyethylene and an outer layer 41 being formed of polyolifin. The piece of shrink tubing 31 is slipped into place over the subassembly including pin 24, washer 30 and center conductor 20, but not enclosing the exposed shield 21. Shrink tubing 31 also does not cover flange 29 of pin holder 26. Referring now to FIG. 3, heat is applied to tubing 31 by means of a suitable tool which pinches the upper end of tubing 31. The applied heat seals such upper end of tubing 31 as well as the material near slot 33. In addition, the heat applied is sufficient to cause the polyethylene inner layer 40 to flow and fill the entire space surrounding center conductor 20, washer 30 and solder 32. In this manner, shrink tubing 31 insulates pin 24, center conductor 20, washer 30 and solder 31 from the exposed shield 21.

Shrink tubing 31, together with washer 30, also serves another purpose. Since connector 16 makes a friction fit with connector pin 24, there is a possibility,-

when removing cable connector from electrode assembly 12, that connector pin 24 will firmly hold connector l6 and move therewith. Without washer 30, pin 24 could slip through and out of pin holder 26, thereby breaking the electrical connection with center conductor 20. Washer 30, however, has an outer diameter which is greater than the diameter of bore 27 in pin holder 26 and effectively prevents pin 24 from being pulled out of pin holder 26 if it sticks too tightly to connector 16 of electrode assembly 12. In addition, since inner layer 40 fills the entire space surrounding conductor 20, washer 30 and solder 32, it also functions to prevent pin 24 from being pulled out of pin holder 26.

The cable subassembly, as shown in FIG. 2, with tubing 31 shrunk down, is then put into a mold, such mold having any desired shape. A conductive molding compound is injected into the mold to form a socket cap, designated 35. During the molding operation, cable 11 is imbedded within the molding compound, cable 11 being positioned at any desired angle relative to the axis of connector pin 24. In addition, because of the manner in which cable 11 is stripped, a permanent electrical connection is made between the exposed shield 21 of cable 11 and the conductive molding material of cap 35. Flange 29 of pin holder 26 is also imbedded in the molding material to firmly position the subassembly of FIG. 2 in socket cap 35.

Socket cap 35 functions, in the first instance, as the outer housing of cable connector 10 and the outer configuration, therefore, may have any desired shape. In addition, socket cap 35 also serves to make electrical connection between shield 21 of cable 11 and outer connector 18 of electrode assembly 12. More specifically, socket cap 35 includes a bore 36, the axis of which is parallel to the axis of connector pin 24. In the present example, bore 36 and connector pin 24 are coaxial. Bore 36 extends from the open end 37 of socket cap 35 to a plane which includes the open end of connector pin 24 and the adjacent end of pin holder 26. This distance is substantially equal to the length of connector 18 of electrode assembly 12. In addition, the diameter of bore 36 is essentially equal to the outer diameter of connector 18 whereby connector 18 may frictionally engage socket cap 35 along the walls of bore 36.

The completed cable connector is shown in FIG. 3.

As cable connector 10 is slipped over the end of electrode assembly 12, inner connector 16 extends into and frictionally engages connector pin 24 whereas outer connector 18 extends into bore 36 and frictionally engages socket cap 35. In this manner, electrical contact is simultaneously completed between inner connector 16 of electrode assembly 12 and center conductor 20 of cable 11 via connector pin 24 and between outer connector 18 of electrode assembly 12 and shield 21 of cable 11 via the conductive molding material of socket cap 35.

It can therefore be seen that in accordance with the present invention, there is provided a novel cable connector 10 which not only eliminates the problems present in the prior art but also adds several unique features. The present method and means of construction completely eliminates the need for expensive metal parts to make connection between shielding 21 and connector 18 since the molded socket cap 35 provides such electrical connection directly. The slow, cumbersome assembly methods are also entirely eliminated. More specifically, it is no longer necessary to swage connector pin 24 since washer 30 in combination with shrink tubing 31 is operative to prevent connector pin 24 from slipping out of pin holder 26 and breaking the electrical connection between pin 24 and center conductor 20. The construction process is also considerably simplified by the elimination of a mechanical means for making an electrical connection between a metal sleeve and the cable shield. Such conventional metal sleeve is entirely replaced by the conductive molding compound which may be molded into any convenient shape to provide these advantages as well as providing the finished configuration. The piece of shrink tubing 31 insulates the center connections from the conductive molding compound as well as strengthening the joint so that the soldered electrical connection cannot be damaged in handling prior to the molding operation.

While the invention has been described with respect to the preferred physical embodiment constructed in accordance therewith, it will be apparent to those skilled in the art that various modifications and improvements may be made without departing from the scope and spirit of the invention. For example, cable connector 10 may be fabricated with various configurations for pin 24, with or without pin holder 26, and with cable 11 at any angle to pin 24. With minor variations, cable connector 10 may be used in any application where an electrical connection is desired on coaxial or multi-conductor cables. Socket cap 35 may be made of a flexible, semi-flexible or rigid material. Accordingly, it is to be understood that the invention is not to be limited by the specific illustrative embodiment, but only by the scope of the appended claims.

I claim:

1. An assembly for connecting a multi-conductor cable to an electrode assembly having inner and outer electrically conductive connectors, comprising:

a socket cap formed of an electrically conductive molding material, said socket cap having a bore therein, said electrode assembly adapted to extend into said bore with said outer connector of said electrode assembly directly contacting the wall of said cap in said bore, said cable being embedded within said cap with a first of the conductors thereof in direct electrical contact therewith whereby electrical connection is made between a socket cap formed of an electrically conductive molding material, said socket cap having a bore therein, said electrode assembly adapted to extend into said bore with said outer connector of said electrode assembly directly contacting the wall of said cap in said bore, said cable being imbedded within said cap with a first of the conductors thereof in electrical contact therewith whereby electrical connection is made between said first a connector pin, said pin being electrically connected to a second of the conductors of said cable, said connector pin being positioned within said cap, said connector pin adapted to contact said said first conductor and said outer connector via nn r connector of said electrode a y; said socket cap; means for electrically insulating said second conduca connector pin, said pin being electrically contor and said connector pin from said cap and said nected to a second of the conductors of said cable, first Conductor; said connector pin being iti d i hi id 10 an elongated, electrically insulative pin holder havcap, said connector pin adapted to contact said mg a bore theret-hrough Said connector P inner connector of said electrode assembly; and tending through a d bore in Sa d pin holder, a pormeans for electrically insulating said second conduction of Said P holder being imbedded in Said tor and said connector pin from said cap and said cap; first conductor, said means for electrically insulatsald connector P bemg a f" m b havmg an ing comprising a shrinkable electrically insulative P?" a q a closed 531d P frlctlonally member, said member being positioned around gegmg Sald Pm m said connector pin and said second conductor, said a f annulus the Inner dlimeter of l annulus member being shrunk to enclose and insulate said bemg less than the Outer fhameter of Sa 1d connec' connector pin and said second conductor from f pm and the uter d1ameter sad arfnuhls said cap and Said first conductor. being greater than the diameter ofsald bore 1n sa d 2. An assembly for connecting a multi-conductor Pm holder f bemg P f over Said cable to an electrode assembly having inner and outer closed end of connector, Second P electrically conductive connectors, comprising? ductor and Sam annulus bemg connected to Sald closed end of said pin whereby said annulus prevents said connector pin from being pulled through and out of said pin holder. 4. An assembly according to claim 3 wherein said second conductor, said annulus and said connector pin are soldered together.

5. An assembly according to claim 3 wherein said means for electrically insulating comprises:

a shrinkable, electrically insulative, tubular member, said member being positioned around said pin conductor and said outer connector via said socket holder and the connection between Said Second conductor, said annulus and said closed end of said a connector Sald pm bemg elecmcaily conconnector pin said member not covering said first nected to a second of the conductors of said cable, conductor Said member being Shrunk to enclose Said coimector pm beimg posmoned wlthm i and insula te said connection from said first conconnector adapted to Contact Sald 40 ductor said first conductor being imbedded within Inner connector of said electrode assembly; and in lectrica] Contact with Said p a shrinkable, electrically insulative member posi- 6 An assembly according to claim 5 wh'erein said tioned around said connector pin and said second bu] member comprises conductor and bein shrunk to enclose and insulate said connector in and said second conductor an mner polyethylene layer and P an outer, polyolifin layer, said outer layer enclosing from 531d f first conductor sald and insulating said connection, said inner layer member compnsmg an mner pPlyethylene layer filling the entire space surrounding said connecand an outer, polyollfin layer, said outer layer entiom closing and insulatmg 531d connector P and 531d 7. A method for assembling a cable connector for second conductor, and said inner layer filling the connecting a multi-conductor cable to an electrode assembly having inner and outer electrically conductive connectors, comprising the steps of:

stripping said cable to expose at least first and second conductors thereof;

entire space surrounding said second conductor and said connector pin. 3. An assembly for connecting a multi-conductor cable to an electrode assembly having inner and outer electrically conductive connectors, comprising:

a socket cap formed of an electrically conductive molding material, said socket cap having a bore therein, said electrode assembly adapted to extend positioning a connector pin in an elongated electrically insulative pin holder;

connecting said first conductor to said connector pin;

i o a 'fi With Said Outer connector of Said positioning an electrically insulating material around electrode assembly directly contacting the wall of id fi t conductor d jd i h ld b not said cap in said bore, said cable being imbedded around said second conductor;

within said cap with a first of the conductors positioning the before-mentioned components intoa thereof in electrical contact therewith whereby mold;

electrical connection is made between said first conductor and said outer connector via said socket filling said mold with a conductive molding material whereby said pin holder, connector pin and first conductor are imbedded within said conductive molding material but said pin and first conductor are separated therefrom by said insulating material and pin holder, and whereby said second conductor in imbedded within and in electrical contact outer diameter of said connector pin, said first conductor and said annulus being connected to said closed end of said pin whereby said annulus prevents said connector pin from being pulled through and out of said pin holder.

9. A method according to claim 7 wherein said step of positioning an electrically insulating material around said first conductor and said connector pin comprises the steps of:

positioning a shrinkable, electrically insulative, tubular member around said pin holder and the connection between said first conductor and said connector pin, said member not covering said second conductor; and

heating said member to seal the openings therein,

thereby enclosing and insulating said connection from said second conductor, said second conductor being imbedded within and in electrical contact with said cap.

with said conductive molding material, said conductive molding material being molded to include a bore concentric with and forward of said connector pin, said electrode assembly adapted to extend into said bore with said outer connector of said electrode assembly contacting said molding 10 material and with said inner connector of said electrode assembly contacting said connector pin. 8. A method according to claim 7 wherein said connector pin is a tubular member having an open end and a closed end, said pin frictionally engaging said pin holder and further comprising the step of:

positioning a thin annulus over said closed end of said connector pin prior to the step of connecting said first conductor to said connector pin, the inner diameter of said annulus being less than the 

1. An assembly for connecting a multi-conductor cable to an electrode assembly having inner and outer electrically conductive connectors, comprising: a socket cap formed of an electrically conductive molding material, said socket cap having a bore therein, said electrode assembly adapted to extend into said bore with said outer connector of said electrode assembly directly contacting the wall of said cap in said bore, said cable being embedded within said cap with a first of the conductors thereof in direct electrical contact therewith whereby electrical connection is made between said first conductor and said outer connector via said socket cap; a connector pin, said pin being electrically connected to a second of the conductors of said cable, said connector pin being positioned within said cap, said connector pin adapted to contact said inner connector of said electrode assembly; and means for electrically insulating said second conductor and said connector pin from said cap and said first conductor, said means for electrically insulating comprising a shrinkable electrically insulative member, said member being positioned around said connector pin and said second conductor, said member being shrunk to enclose and insulate said connector pin and said second conductor from said cap and said first conductor.
 2. An assembly for connecting a multi-conductor cable to an electrode assembly having inner and outer electrically conductive connectors, comprising: a socket cap formed of an electrically conductive molding material, said socket cap having a bore therein, said electrode assembly adapted to extend into said bore with said outer connector of said electrode assembly directly contacting the wall of said cap in said bore, said cable being imbedded within said cap with a first of the conductors thereof in electrical contact therewith whereby electrical connection is made between said first conductor and said outer connector via said socket cap; a connector pin, said pin being electrically connected to a second of the conductors of said cable, said connector pin being positioned within said cap, said connector pin adapted to contact said inner connector of said electrode assembly; a shrinkable, electrically insulative member positioned around said connector pin and said second conductor and being shrunk to enclose and insulate said connector pin and said second conductor from said cap and said first conductor, said member comprising an inner, polyethylene layer and an outer, polyolifin layer, said outer layer enclosing and insulating said connector pin and said second conductor, and Said inner layer filling the entire space surrounding said second conductor and said connector pin.
 3. An assembly for connecting a multi-conductor cable to an electrode assembly having inner and outer electrically conductive connectors, comprising: a socket cap formed of an electrically conductive molding material, said socket cap having a bore therein, said electrode assembly adapted to extend into said bore with said outer connector of said electrode assembly directly contacting the wall of said cap in said bore, said cable being imbedded within said cap with a first of the conductors thereof in electrical contact therewith whereby electrical connection is made between said first conductor and said outer connector via said socket cap; a connector pin, said pin being electrically connected to a second of the conductors of said cable, said connector pin being positioned within said cap, said connector pin adapted to contact said inner connector of said electrode assembly; means for electrically insulating said second conductor and said connector pin from said cap and said first conductor; an elongated, electrically insulative pin holder having a bore therethrough, said connector pin extending through said bore in said pin holder, a portion of said pin holder being imbedded in said socket cap; said connector pin being a tubular member having an open end and a closed end, said pin frictionally engaging said pin holder; and a thin annulus, the inner diameter of said annulus being less than the outer diameter of said connector pin and the outer diameter of said annulus being greater than the diameter of said bore in said pin holder, said annulus being positioned over said closed end of said connector pin, said second conductor and said annulus being connected to said closed end of said pin whereby said annulus prevents said connector pin from being pulled through and out of said pin holder.
 4. An assembly according to claim 3 wherein said second conductor, said annulus and said connector pin are soldered together.
 5. An assembly according to claim 3 wherein said means for electrically insulating comprises: a shrinkable, electrically insulative, tubular member, said member being positioned around said pin holder and the connection between said second conductor, said annulus and said closed end of said connector pin, said member not covering said first conductor, said member being shrunk to enclose and insulate said connection from said first conductor, said first conductor being imbedded within and in electrical contact with said cap.
 6. An assembly according to claim 5 wherein said tubular member comprises: an inner, polyethylene layer; and an outer, polyolifin layer, said outer layer enclosing and insulating said connection, said inner layer filling the entire space surrounding said connection.
 7. A method for assembling a cable connector for connecting a multi-conductor cable to an electrode assembly having inner and outer electrically conductive connectors, comprising the steps of: stripping said cable to expose at least first and second conductors thereof; positioning a connector pin in an elongated electrically insulative pin holder; connecting said first conductor to said connector pin; positioning an electrically insulating material around said first conductor and said pin holder but not around said second conductor; positioning the before-mentioned components into a mold; filling said mold with a conductive molding material whereby said pin holder, connector pin and first conductor are imbedded within said conductive molding material but said pin and first conductor are separated therefrom by said insulating material and pin holder, and whereby said second conductor in imbedded within and in electrical contact with said conductive molding material, said conductive molding material being molded to include a bore concentric with and forward of said connector pin, said electrode assemBly adapted to extend into said bore with said outer connector of said electrode assembly contacting said molding material and with said inner connector of said electrode assembly contacting said connector pin.
 8. A method according to claim 7 wherein said connector pin is a tubular member having an open end and a closed end, said pin frictionally engaging said pin holder and further comprising the step of: positioning a thin annulus over said closed end of said connector pin prior to the step of connecting said first conductor to said connector pin, the inner diameter of said annulus being less than the outer diameter of said connector pin, said first conductor and said annulus being connected to said closed end of said pin whereby said annulus prevents said connector pin from being pulled through and out of said pin holder.
 9. A method according to claim 7 wherein said step of positioning an electrically insulating material around said first conductor and said connector pin comprises the steps of: positioning a shrinkable, electrically insulative, tubular member around said pin holder and the connection between said first conductor and said connector pin, said member not covering said second conductor; and heating said member to seal the openings therein, thereby enclosing and insulating said connection from said second conductor, said second conductor being imbedded within and in electrical contact with said cap. 